Dredging
Without dredgers the quality of the Le Havre port would not be the same. Acting as men behind the scenes, dredge operators continuously maintain seabeds allowing any ship, however big (some longer than the height of the Eiffel tower) to stopover at Le Havre 24/7 throughout the year in the best conditions of safety.
Sea access maintenance: a crucial collective job when operating a port
Tidal action and rainfall constantly modify the port of Le Havre seabeds. Each year tons of sediment (sludge or silica) buildup at the bottom of the sea and reduce the draft necessary to the traffic of ships. It therefore becomes necessary to maintain this access to the sea daily (channels, basins…) which means dredging some 3 million m3 of material each year. The mode of operation used for dredging at Le Havre port respects the environment and complies with national and international regulation. The Protocol monitoring Dumping relates to water and sediment quality as well as marine wildlife on site.
To ensure the maintenance of sea access port authorities operate Gambe d’Amfard, a powerful 60 meter long boat especially dedicated to the recovery of sediment. “Dredging is operated on a 12 hour a day, daily basis” mentions Didier, chief engineer on the ship: “two teams of 7 people rotate each week. Each crew is divided in two different activities: deck management and engine room management. It is a multipurpose dredger which offers two dredging options: sediments are either removed by a crane located on the deck (20 tons capacity skip) or a drag arm is used (suction pipe lowered to the bed to suck sludge)”.
On a ship equipped with engines of over 5 000 KW total power, hydraulic, pneumatic, computer and automated systems, the position of chief engineer is crucial. He must monitor and coordinate the implementation of mechanical activities while ensuring safety on board: from the propulsion of the ship to the operation of the dredging systems. “Imagine dredging as a series of mechanical movements that must be converted and transformed. The energy comes from the engines then supplies all the systems used to make it work: radars, propellers, crane, computers, etc.” not to mention that dredging techniques changed a lot during the few last decades, especially thanks to the support of IT which made devices more accurate and safer. “I come from a school of mechanical engineers called “the royal”, belonging to the Marine Nationale. Then during my career I passed a chief engineer license at the Ecole Nationale de la Marine Marchande” explains Didier.
Dredging operations: accuracy and safety first
Ronan, chief officer, stands on the upper deck of the Gambe d’Amfard. He also trained at ENMM in order to obtain a higher diploma from Marine Marchande (Merchant navy). This profession involves the navigation of the ship in collaboration the master and maneuvering it during dredging operations. The chief officer is responsible for safety measures, first aid equipment, nautical literature and dredger maintenance. Such responsibility also involves the ability to manage stress. “It means constant management. We navigate in difficult waters because of an intense marine traffic” adds Ronan. “Dredging operations are not operated by chance. We work with much detailed hydrographic maps to organize dredging and very accurate instruments to navigate such as radars and electronic maps. We can therefore remove sediment with great accuracy (up to about 50 cm). “One of the human qualities required by the job? “Team spirit, without a doubt. One must be able to live and work with others in a confined space and help further than his own assignment to ensure the success of a mission”.
Source: multiple Internet sources, specialized literature, testimonials (Pratic-Export, Pôle-emploi cards, Wikipedia, Onisep, CNRTL, Umep à la Page…)
